This invention relates to apparatus for supporting the lower end of a mine roof support assembly which is used in inclined workings.
A known type of mine roof support assembly is constituted by a plurality of roof support units positioned side-by-side along, for example, a longwall face. Each of the units has a roof shield supported on a floor sill by means of hydraulic props. In mining operations involving steeply inclined seams, the floor of the working is also steeply inclined, in which case means must be provided for preventing the roof support units slipping in the direction of dip.
One known method of preventing such slip is to provide the lowest roof support unit with support apparatus which fixes that unit rigidly to the goaf side of the face-side conveyor at a fixed angle thereto. Thus, the support apparatus provides lateral support for this lowest roof support unit. Under normal conditions, it is possible for this system to counteract the tendency of the entire roof support assembly to slip down the inclined floor of the working.
A known type of support apparatus has a rigid beam for laterally supporting the lowermost roof support unit. The rigid beam is attached to the conveyor which extends along the working. The beam is angularly adjustable in a plane parallel to the floor of the working, and can be locked in any desired angular position. Although this form of apparatus provides adequate support, it does not permit accurate alignment of the roof support units without employing additional means such as an anchoring device. This disadvantage results from it being impossible for this type of apparatus to adjust the position of the lowermost roof support unit only in the direction of face advance (that is to say without adjusting the position of that unit in the direction of the longwall working). The need to use additional means such as an anchoring device requires considerable expenditure of power. Moreover, such devices are difficult to control, particularly as they are situated in the congested end regions of longwall installations.
The aim of the invention is to provide support apparatus which does not suffer from these disadvantages.